Authorize known cc members only

[lehins]

Description

In order to prevent garbage hot key authorizations we fail on certificates that mention cold credentials that do not exist somewhere in the ledger state, be it in current constitutional committee or in one of active proposals.

Thanks to @Hornan7 for reporting this issue.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated
• When applicable, versions are updated in .cabal and CHANGELOG.md files according to the
  versioning process.
• The version bounds in .cabal files for all affected packages are updated. If you change the bounds in a cabal file, that package itself must have a version increase. (See RELEASING.md)
• All visible changes are prepended to the latest section of a CHANGELOG.md for the affected packages. New section is never added with the code changes. (See RELEASING.md)
• Code is formatted with fourmolu (use scripts/fourmolize.sh)
• Cabal files are formatted (use scripts/cabal-format.sh)
• hie.yaml has been updated (use scripts/gen-hie.sh)
• Self-reviewed the diff

[aniketd]

LGTM 👍

[teodanciu]

Changelog for conway is missing:

* Added `ConwayCommitteeIsUnknown` predicate failure to  `ConwayGovCertPredFailure`  
* Added `cgceCurrentCommittee` and `cgceCommitteeProposals` to `ConwayGovCertEnv`